2003 automatic kia sorento turbo diesel, smoking very much thick grey smoke

black smoke is over fuel and in a diesel with a turbo that indicates that
1 the turbo variable vanes are not adjusting to low rpm
2- the turbo turbine wheel is not spinning up
3-the intercooler or hoses are leaking boost air
4-- bad injectors -- squirting and not atomizing

Dark grey/black smoke is excess fuel/ poor combustion. Get a garage to check the turbo function but you don't say how many miles its done so it may need an engine service including things like the emissions control valves etc.

Check:
1. EGR Valve
2. Turbo
Do you have a lot of smoke?
If yes, what colour?
- bueish, white or black (very important to find out the problem).

sounds like the EGR valve get clogged by the diesel sludge, it could be cleaned, depending on the valve, one side could get blocked off. but we often changed the valve.

Black smoke = excess fuel. Could be o2 sensor, blocked fuel pressure regulator etc... should have vehicle scaned they may be able to extract a code, if not a fuel pressure test would be good to

from what you describe,sounds like your turbo is shot..(but could be other things,need much more info.)

if this is a diesel kia then smoking is not a very bad sign. diesels tend to smoke when the diesel injectors are clogged up. this can happen with very poor dirty diesel fuel. take the kia in to a good mechanic. not the agents or kia cause they are going to rip you off. or there is a solvent you can buy at a carparts&accessories that can unclog. just ask for assistance. a diesel starts smoking when the diesel injectors are clogging up. good luck.

blue smoke would show a lean condition. most likely a fuel line leak between pump and tank not a pressure leak.or a check valve is allowing fuel to run back to the tank

Sorry to say this but you have a blown head gasket, this white smoke is diesel and water mixed, depends on how far you want to go now if you want to strip down or get a tablet that I mean a special tablet that you put in the radiator that does do an instant and effective repair, garages don't tell you this as it's for them only if you know what I mean, you get this tablet of the internet as garages not sell you one. please do not use the liquid sealers you can get to repair radiators.

Hope you get sorted with out to much cost.
Good Luck

on my sorento same problem and its solved vacuum pump on turbo, now ok, sorry for bad english, vacuum membrane is broken